115mm Celotex Thermaclass Cavity Wall 21 Full Fill Insulation Board T&G 1190mm x 450mm (2.68m2/Pack)
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PIR full_fill cavity wall board with tongue_and_groove edges to minimise heat loss at joints. Suitable for 115mm masonry cavities, offering excellent thermal performance with a low conductivity of 0.021W/mK.
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Product Overview
PIR full_fill cavity wall board with tongue_and_groove edges to minimise heat loss at joints. Suitable for 115mm masonry cavities, offering excellent thermal performance with a low conductivity of 0.021W/mK.
Delivery & Returns Information
How Our Delivery Works
We work with a nationwide network of trusted suppliers. As a result, items in your basket may be supplied by different suppliers and delivered separately. Where this applies, you'll see multiple delivery charges at checkout. We always aim to group products from the same supplier to keep delivery costs as low as possible.
Delivery Areas & Charges
Delivery charges listed on our website apply to mainland UK, excluding the following postcode areas: AB, CF, DD, DG, EH, FK, KA, KW, KY, IV, LA, LD, LL, ML, NP, PA, PH, SA, SY & TD
If your delivery address falls within one of these postcode areas, we’ll be in touch before processing your order to confirm any additional delivery costs.
Please note: We do not currently offer delivery outside the UK mainland.
Standard (Nationwide) Delivery
| Insulation, Plasterboard and Drylining Products | |
|---|---|
| ORDER VALUE | DELIVERY CHARGE |
| Under £350 | £35 ex. VAT |
| Over £350 ex. VAT | FREE |
| Timber & Sheet, Building Materials, Joinery and Gardens & Landscaping Products | |
| ORDER VALUE | DELIVERY CHARGE |
| Under £100 | £20 ex. VAT |
| Between £100 - £300 ex. VAT | £10 ex. VAT |
| Over £300 ex. VAT | FREE |
| Screws & Fixings and Adhesives & Sealants | |
| ORDER VALUE | DELIVERY CHARGE |
| Under £50 | £5 ex. VAT |
| Over £50 ex. VAT | FREE |
Express Delivery
| Express Delivery - Insulation and Plasterboard & Drylining | |
|---|---|
| ORDER VALUE | DELIVERY CHARGE |
| Under £400 | £50 ex. VAT |
| Over £400 ex. VAT | £35 ex. VAT |
| Express Delivery - Timber & Sheet, Building Materials, Joinery and Gardens & Landscaping Products | |
| ORDER VALUE | DELIVERY CHARGE |
| Under £300 | £50 ex. VAT |
| Over £300 ex. VAT | £35 ex. VAT |
Returns
We offer a 30 day returns policy on any faulty products.
Key Features
- {{holiday_village}} Designed for full fill cavity wall applications
- {{thermostat}} Low emissivity foil facing for improved thermal performance
- {{menu_open}} Can be installed with up to a 10mm residual cavity
- {{check_circle}} Accommodates mortar squeeze
Technical Specification
| Material Type: | PIR |
|---|---|
| Thickness: | 115mm |
| Width: | 450mm |
| Length: | 1190mm |
| Pieces Per Pack: | 5 |
| Sales Unit: | Pack |
| Sales Unit Coverage: | 2.68m2 |
| Brand: | Celotex |
| Thermal Conductivity: | 0.021W/mK |
Technical Downloads
Product Overview
Celotex Thermaclass Cavity Wall 21 Full Fill Insulation Board with a 115mm thickness and 1190mm × 450mm dimensions.
High-performance rigid polyisocyanurate (PIR) insulation board designed for use in full fill masonry cavity wall applications. Manufactured with a low emissivity foil facing, it delivers exceptional thermal conductivity of 0.021 W/mK, helping achieve low U-values while reducing overall wall thickness requirements.
The tongue and groove edge profile provides a tight, secure fit, minimising air gaps and thermal bridging. The board can be installed as a full fill solution or with a residual cavity of up to 10mm to accommodate mortar squeeze and simplify installation.
Lightweight, rigid, and easy to handle, the board fits standard wall tie spacing, supporting fast, efficient on-site fitting. The 115mm thickness is ideal for deeper cavity walls in high-performance housing and commercial developments.
Features & Benefits
- Outstanding thermal performance: Declared thermal conductivity of 0.021 W/mK reduces wall thickness while achieving low U-values.
- High performance facer: Low emissivity foil facing improves performance in cavities with up to 10mm air space.
- Precision fit: Tongue and groove edge detail ensures close jointing and minimal thermal bridging.
- Ease of installation: Sized for standard wall tie spacing; light, rigid boards are simple to transport and fit.
- Certified performance: BBA certified for full fill cavity wall use under Certificate 16/5343.
- Thickness: 115mm board ideal for deeper cavity walls in high-performance housing and commercial developments.
Applications
- Full fill cavity walls: Suitable for use between masonry leaves in domestic and commercial buildings.
- New build housing: Provides excellent U-value compliance in energy-efficient walls.
- Residual cavity installation: Can be fitted with a 10mm residual cavity to accommodate mortar squeeze.
- Thermal upgrade projects: Ideal for meeting advanced energy performance requirements.
Installation Guidance
- Preparation: Ensure cavity surfaces are clean and free from debris before installation.
- Board placement: Install boards with tongue and groove joints interlocked and staggered in brick bond pattern.
- Fixing method: Secure with appropriate retaining clips to wall ties as construction progresses.
- Joint sealing: Ensure tight-fitting joints with no gaps; seal edges as required by specification.
- Residual cavity: Maintain up to 10mm air space where design requires.
- Protection: Keep boards dry and covered until fully installed.
Compliance & Performance
- Material specification: Rigid PIR insulation with low emissivity foil facing.
- Thermal conductivity: 0.021 W/m·K (to BS EN 13165).
- Fire performance: Euroclass E reaction to fire to BS EN 13501-1.
- Compressive strength: ≥120 kPa at 10% compression.
- Water vapour resistance: High resistance due to foil facing.
- Certification: BBA certified (No. 16/5343) for full fill cavity wall systems.
- Environmental compliance: Manufactured under ISO 14001:2015 Environmental Management System.
- Standards compliance: UKCA marked to BS EN 13165 for factory-made rigid polyurethane (PU) insulation.
- Important note: Install and maintain in accordance with Celotex guidance and BBA certification details.
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